[Ocfs2-devel] [PATCH] ocfs2: fix BUG due to uncleaned localalloc during mount

From: Joseph Qi <joseph.qi@huawei.com>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [PATCH] ocfs2: fix BUG due to uncleaned localalloc during mount
Date: Wed, 25 Nov 2015 10:01:00 +0800	[thread overview]
Message-ID: <5655165C.9000709@huawei.com> (raw)
In-Reply-To: <D1E4D02760513D4B90DC3B40FF32AF355EDCB027@H3CMLB12-EX.srv.huawei-3com.com>

Hi Changkuo,
Yes, it's safe.
ocfs2_begin_local_alloc_recovery will firstly copy it out and then
assign to osb->local_alloc_copy, which will be queued later in
ocfs2_queue_recovery_completion. And ocfs2_complete_local_alloc_recovery
will sync the local alloc to main, which is the same thing you have
pointed out in fsck.
Local alloc bits have already been allocated from global bitmap and it
means there is no any conflicts with others. Even crash happens directly
after ocfs2_begin_local_alloc_recovery, the only consequence is some
bits will be lost, and for this case we cannot do any more during ocfs2
recovery.

On 2015/11/25 9:08, Shichangkuo wrote:
> Hi?Joseph Qi
> In this situation,  ocfs2_begin_local_alloc_recovery will be called, and finally call ocfs2_clear_local_alloc, which direct clear la bitmap, like:
> 
>         alloc->id1.bitmap1.i_total = 0;
>         alloc->id1.bitmap1.i_used = 0;
>         la->la_bm_off = 0;
>         for(i = 0; i < le16_to_cpu(la->la_size); i++)
>                 la->la_bitmap[i] = 0;
> 
> It's different from fsck.ocfs2, also called function ocfs2_clear_local_alloc, but this function does more than direct clear la bitmap.
> Global bitmap will also be cleared.
> So, does this patch data-safe?
> 
> 
> -----????-----
> ???: ocfs2-devel-bounces at oss.oracle.com [mailto:ocfs2-devel-bounces at oss.oracle.com] ?? Joseph Qi
> ????: 2015?11?24? 21:38
> ???: Andrew Morton
> ??: Mark Fasheh; ocfs2-devel at oss.oracle.com
> ??: [Ocfs2-devel] [PATCH] ocfs2: fix BUG due to uncleaned localalloc during mount
> 
> Tariq has reported a BUG before and posted a fix at:
> https://oss.oracle.com/pipermail/ocfs2-devel/2015-April/010696.html
> 
> This is because during umount, localalloc shutdown relies on journal shutdown. But during journal shutdown, it just stops commit thread without checking its result. So it may happen that localalloc shutdown uncleaned during I/O error and after that, journal then has been marked clean if I/O restores.
> Then during mount, localalloc won't be recovered because of clean journal and then trigger BUG when claiming clusters from localalloc.
> 
> In Tariq's fix, we have to run fsck offline and a separate fix to fsck is needed because it currently does not support clearing out localalloc inode. And my way to fix this issue is checking localalloc before actually loading it during mount. And this is somewhat online.
> 
> Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
> ---
>  fs/ocfs2/localalloc.c | 19 ++++++++++++-------  fs/ocfs2/localalloc.h |  2 +-
>  fs/ocfs2/super.c      | 17 ++++++++++++++---
>  3 files changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c index 0a4457f..ceebaef 100644
> --- a/fs/ocfs2/localalloc.c
> +++ b/fs/ocfs2/localalloc.c
> @@ -281,7 +281,7 @@ bail:
>         return ret;
>  }
> 
> -int ocfs2_load_local_alloc(struct ocfs2_super *osb)
> +int ocfs2_load_local_alloc(struct ocfs2_super *osb, int check, int
> +*recovery)
>  {
>         int status = 0;
>         struct ocfs2_dinode *alloc = NULL;
> @@ -345,21 +345,26 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb)
>         if (num_used
>             || alloc->id1.bitmap1.i_used
>             || alloc->id1.bitmap1.i_total
> -           || la->la_bm_off)
> +           || la->la_bm_off) {
>                 mlog(ML_ERROR, "Local alloc hasn't been recovered!\n"
>                      "found = %u, set = %u, taken = %u, off = %u\n",
>                      num_used, le32_to_cpu(alloc->id1.bitmap1.i_used),
>                      le32_to_cpu(alloc->id1.bitmap1.i_total),
>                      OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);
> +               status = -EINVAL;
> +               *recovery = 1;
> +               goto bail;
> +       }
> 
> -       osb->local_alloc_bh = alloc_bh;
> -       osb->local_alloc_state = OCFS2_LA_ENABLED;
> +       if (!check) {
> +               osb->local_alloc_bh = alloc_bh;
> +               osb->local_alloc_state = OCFS2_LA_ENABLED;
> +       }
> 
>  bail:
> -       if (status < 0)
> +       if (status < 0 || check)
>                 brelse(alloc_bh);
> -       if (inode)
> -               iput(inode);
> +       iput(inode);
> 
>         trace_ocfs2_load_local_alloc(osb->local_alloc_bits);
> 
> diff --git a/fs/ocfs2/localalloc.h b/fs/ocfs2/localalloc.h index 44a7d1f..a913841 100644
> --- a/fs/ocfs2/localalloc.h
> +++ b/fs/ocfs2/localalloc.h
> @@ -26,7 +26,7 @@
>  #ifndef OCFS2_LOCALALLOC_H
>  #define OCFS2_LOCALALLOC_H
> 
> -int ocfs2_load_local_alloc(struct ocfs2_super *osb);
> +int ocfs2_load_local_alloc(struct ocfs2_super *osb, int check, int
> +*recovery);
> 
>  void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb);
> 
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index 2de4c8a..4004b29 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -2428,6 +2428,7 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>         int status;
>         int dirty;
>         int local;
> +       int la_dirty = 0, recovery = 0;
>         struct ocfs2_dinode *local_alloc = NULL; /* only used if we
>                                                   * recover
>                                                   * ourselves. */
> @@ -2449,6 +2450,16 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>          * recover anything. Otherwise, journal_load will do that
>          * dirty work for us :) */
>         if (!dirty) {
> +               /* It may happen that local alloc is unclean shutdown, but
> +                * journal has been marked clean, so check it here and do
> +                * recovery if needed */
> +               status = ocfs2_load_local_alloc(osb, 1, &recovery);
> +               if (recovery) {
> +                       printk(KERN_NOTICE "ocfs2: local alloc needs recovery "
> +                                       "on device (%s).\n", osb->dev_str);
> +                       la_dirty = 1;
> +               }
> +
>                 status = ocfs2_journal_wipe(osb->journal, 0);
>                 if (status < 0) {
>                         mlog_errno(status);
> @@ -2477,7 +2488,7 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>                                 JBD2_FEATURE_COMPAT_CHECKSUM, 0,
>                                 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
> 
> -       if (dirty) {
> +       if (dirty || la_dirty) {
>                 /* recover my local alloc if we didn't unmount cleanly. */
>                 status = ocfs2_begin_local_alloc_recovery(osb,
>                                                           osb->slot_num,
> @@ -2490,13 +2501,13 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>                  * ourselves as mounted. */
>         }
> 
> -       status = ocfs2_load_local_alloc(osb);
> +       status = ocfs2_load_local_alloc(osb, 0, &recovery);
>         if (status < 0) {
>                 mlog_errno(status);
>                 goto finally;
>         }
> 
> -       if (dirty) {
> +       if (dirty || la_dirty) {
>                 /* Recovery will be completed after we've mounted the
>                  * rest of the volume. */
>                 osb->dirty = 1;
> --
> 1.8.4.3
> 
> 
> 
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